Air conditioning system



y 1942. LE R'oY H. PLUM 2,282,210

AIR CONDITIONING SYSTEM Filed Jan 22, 1937 3 Sheets-Sheet 1 fiverz'tor 27303 1;. PZum :9- Azzome y y 1942- LE ROY H. PLUM v 2,282,210

- AIR CONDITIONING SYSTEM Q Filed Jan. 22, 1937 v 3 Sheets-Sheet 2 H7 5 7. v i g. 462 Egg? 5 15s 67- I W:

2 LFEROZ/ J 7: pz I l, v

May 5, 1942.; LE ROY H. PLUM 2,282,210

7 AIR CONDITIIONING SYSTEM Filed Jan. 22, 1937 3 Sheets- Sheet 3 Irzveiztcf' B LQROyE-PZum UNITED, STATE Patented May 5, 1942 Le Roy H. Plum, Collingswood, N.J., ass'ignor to I Minneapolis-Honeywell Regulator Company, Minneapolis, Minn, a corporation of Delaware Application January 22, 1937. Serial nmizt'm routines. (Cl.98--33) 1 a L This invention relates to airconditioning systems in general and more particularly to air conditioning systems as applied to a building having a plurality of zones.

An object of this invention is to provide an air conditioning system for a building having a plurality of 7 zones wherein heat exchangers in each of the zones provide means forheating and cooling their respective zones, wherein conditioned air is supplied to all of the zones mainly" for ventilating purposes and wherein the conditioned air-supplying means is controlled to maintain a predetermined pressure dlflerential between the air pressure in the building andthe outside air pressure to prevent infiltration of outside air.

Another object of this invention is to provide a control system for the circulation of heating and cooling fluid through a plurality of, heat exchangers whereby a substantially uniform rate ofcirculation of the heating or cooling fluid is obtained along with a means for adjusting the rate of circulation of the heating and cooling fluid whereby the rate of heat exchange may be increased or decreased. This gives extremely ply of heating fluid and cooling fluid to a plurality of heat exchangers,

Still another object of this invention is to provide an air conditioning system for a building having a plurality of zones wherein a predeter-- mined pressure differential is maintained be- 35 tween the air pressure within the building and the air pressure outside of the building to prevent inflltration of outside air along with indicating means for indicating the differential in 40 pressure effective at any zone.

A further object of this invention is to provide a means for preventing the supply of air to a zone if the differential in pressurebetween the air pressure of that zone and the outside air pressure decreases to a predetermined value.

Still another object of this invention is to provide an air conditioning system for a building having a plurality of zones wherein the supply of conditioned air to all of the zones is prevented in case a fire occurs in the ductwork adjacent an of the zones.

The combination of the various features of this invention into a complete air conditioning system for obtaining new and beneficial results also forms object of this invention.

drawings.

Other objects and advantages will become apparent. to those skilled in the art upon reference to the accompanying specification. claims and Forga more thorough understanding of this invention reference is made to the accompanying drawings in which p 'Figure 1 dlagrammatically'discloses a building with the control system of thisinvention applied thereto, a

Figure 2 illustrates the manner in which the supply of cooling fluid or heating fluid to the unit conditioners is controlled. I

' Figure 3 illustrates the manner in which the compressors, of the refrigerating apparatus are controlled. r Figure 4 is a view showing the manner in which the three-wayfvalve which controls the temperature of cooling fluid supplied to the unit conditioners is controlled. 1 f

" Figure 5 illustrates-the. manner in which the temperature of the heating fluid delivered to the unit conditioners is accomplished.

Figure 6 illustrates a dew-point control for, the cooling fluid circulating pump.

Figure '7 illustrates the manner in which the motors utilized in this invention may operate the dampers. Figure 8 isa wiring diagram showing the operation of the various dampers and motors utilized in this invention. I 9

Referring now to Figure l the building to be air conditioned is generally designated at In and is shown for purposes of illustration tohave a 'plurality of zones, comprising a first floor having rooms H and I2. a second floor having a room ll, 9. third floor having rooms M and. I5 and a fourth floor having rooms l5 and I1, although the building may have any number of rooms or an number of floors. The second floor is shown to have a corridor It, the third floor corridors l9 and 2|! and the fourth floor corridors 2| and 22. Doors 23 provide communication between the corridors and the rooms. The rooms are shown 3 to be provided with windows 24. The building 0 ing. The air conditioning apparatus 28 is of the usual type for delivering air at a desired temperature value and moisture content value to a duct 2'! which extends downwardly into the building I. Since this air conditioning apparatus' may be of any well known typ a further between livered into the corridor 18. Similarly, dampers .1' ond and third floors are atively highstatic pressure and thisconditioned f in construction to motor ,40; that is, these motors An opening having adamper 38 communicates the passage 29 and thecorridor l8 so that conditioned air from the passage 29 is de- 3l and 32 control the supply. of conditioned air to a the corridors l3 and 28, and also dampers 33 and 34' control the supply of conditioned air to the corridors" 2| and-22. ;"Thedoors 23on the secshown tohave grills35 for admitting conditioned air from the corridors into the rooms. iOn the fourth floor the grills p are shown to be grills 38 located above the doors 23 for admitting conditioned air into the rooms I 8 and H. In accordance with this invention, cone ditioned air is delivered to the corridors at a relair is therefore forced through the grills into the rooms and then out through the crevices around the windows 24. In this manner a static'pressure is built up in thebuilding to prevent infiltration through thewindows of hot air in the summer timeiandcold airin the winter time. Thespei cific manner inwh ich this positive static pres- ,sure is maintained will be pointed out more fully ,hereafter-.. f f Y 7 e four fans'21 are controlled by iour motors one of which. is shown at 38infF'igurej 1 and eac ran outlet is provided with a damper '38" which is controlledfby a motor 48 of usual ,design. The-motor may be of the type'that I opens the damperf 39 when electrical energy is supplied theretogand closes the damper 39 by means of springs; gravity or other means. i when 'the supply. of electrical energy is cutiofi. A further description thereforeof the motor '48 is not considered necessary v V The damper 38fisfcontrolled by a motor 42, the dampers 3| and 32 bymotor's 43r and and the'dampers 33 and 134 byjmotors 45. and 48; The motors42, 43, 44'; 45 and 48 maybe similar Y may open' their respective dampers whenelectrical energy is supplied thereto "and close their dampers when the supply of energy is cut off.

Four fans, one of 'jwhich is shown at", are

3 located on the second floor and deliver outdoor: air into 'anair conditioning apparatus 48. This\air conditioning apparatus" may bein all respects'similar' to air conditioning apparahis 28 located on'the roof and therefore this air conditioning apparatus '48 supplies 'conditioned. air an "desiredf temperat'ure value and 1a desirdfiinqisture content value to a" duct '50. "The duct 58 connects into a horizontal duct andthis' duct 5| delivers conditioned air to the spaces 'll'and l2 on the first floor. The supply of from the duct 8| to the space H is controlled by dampers 52 and 53 and the supply of" air tothe space i2*i s"controlledlby dampers 5o '84and u; v j I "The fansv 48 are eachoperated by a motor 58 and associated with "the outlet of each fan 48 is a damper 8'! controlled by-a motor 58; in all respects the same as motorf 40. In other 'words, when electrical energy is supplied to the motor 58 the damper" 81 i'sopened and when the supply of electrical energy is cut'ofl, the damper 'llis'closed.'- 1' -Thedampers 52, 53, 54 and 55 controlling the supply of conditioned air to the spaces II and are operated by motors 58, 88, 8| and 82 respectively. These'motors are preferably of the 'proportioning type and also the-spring return type 1 as illustrated in Patent No. $032,658 7 -toa heat exchanger 13.

granted to w.,H. Gille time. s, 1936. Wheii electrical energy is supplied to these motors they move'the dampers 52, .53, 54 and 55 to a desired open position and when the supply of electrical energy is cut off the dampers. are moved to a closed position by means of springs, gravitypor other means.

Although the air conditioning apparatus as and 49 deliver air to the buildinggat a given condition, heating of :the building inwinter time and cooling of the building in the summer time is accomplished mainly by unit conditioners 85, located, in'each room. .Theseunit conditioners" 'may comprise a heat exchanger 86 to which is supplied either heating fluid or cooling fluid and a fan 81 forcirculating theroom air over the heat exchangers .88.. In this, manner the majority of the heating and cooling of the building is accomplished by unit'condition'ers while the humidityof the air is primarily controlled by the air conditioning apparatus 28 and49." A boiler 88 is located in the basement 2 5; The boiler 89 may befired'by Ya stoker-or oil burner, or any 'other'flr'ing means, under the control of .a pressure controller 1| responsive to steam; pressures inv the boiler 88. Byreason of the "pressure controller .11 the stoker or oil'burner;

18" is operated to: maintain a" (constant steam pressurwithinethe boiler 89. Steam is taken from the'boiler 88 by a pip'eil2 and delivered The condensed steam flows from the heat exchanger 'l3 through a return pipe "back to the boiler as. The amount of steam-delivered to the heat exchanger .13

from the boiler 89 controlledby a valve -15 which in turn is operated by a proportioning motor 18 which may be of the type shownand described in-Patent No. 1,989,972 granted to 'Lewis L. Cunningham on February 5, 1935,.or: 4o-

' 7 Taylor on January 14, 1936.

shown in Patent No. 2,028,110, granted to D'. G.

Water isheated in theheat exchanger 13 and flows through a pipe 14, a valve 15 and a pipe "to supply header l1. Thezvalve' I5 is closed inthe summer time and opened in thewinteh time. Risers l8 lead from the'supply'header ll and are connected to the heat, exchangers 86 of theunit conditioners 85." Returnrisers 19 con- -nected also to the heat 'exchangers 880i the unitconditioners 85 terminate .in a return header .88. The return header 88.is connected by a pipe 8| to an electrically operated circu- 'lating pump 82. The circulating pump 82 discharges through avalve 83 into a'pipe 85 which in turn is connected: by a valve 88 and a pipe I 8-! to the heat exchanger". The valve 83 is it isseen that water .is-heated in the heat exchanger l3and is circulated by the circulating pump 82 thronghthe heat exchangers 88 of the unit conditioners 85. and returned to the heat exchanger 13 for reheating. In other words, a closed system is provided for supplyinghot .wa-

ter to the unit conditioners 85 for heating purposes in the wintertime. 9 The'proportioning motor supply of steam to the heat exchanger 13 is controlled by a temperature controller 89 responsive to the temperature of the water leaving the heat exchanger 13 and by a compensator 88 responslve to outdoor temperatures.

The arrangement is such that as the hot watertemperaturede- .18 which controls the creases the valve I is moved toward an open position to supply more steam and asthe hot water temperature increases, the valve I5 is moved toward a closed position to decrease the supply of steam. The compensator 88 adjusts the eflec- 5 tive setting of the temperature controller to raise the'sett'ing thereof as the outdoor temperature decreases and to lower the setting thereof as the outdoor temperature increases. In this manner hot water is supplied to the unit conditioners 65 at a temperature which varies in accordance with outdoor temperatures. In other words, as the'outdoor temperature increases the heating eflfectgof the unit conditioners 88 is decreased and as the outdoor temperature decreases the heating effect is increased. The specific manner in which the temperature controller 88 and the outside compensator 88 control the proportioning motor-I8 is shown in Figure 5 and is described later. 4

The valve 88 located on the outlet side of the circulating pump 82 is controlled by the proportioning motor 84 which in turn is'controlled by a pressure controller 8| responsive to the head pressure in the heating system. when the 5 head pressure in the heating system increases the valve 88 is moved toward aclosed position and when the head pressure decreases the valve 88 is moved toward an open position. In this manner a constant head pressure in the hot water heating system i at all times maintained. By raising the setting of the pressure controller" 8| the head pressure and therefore the rate of flow of the hot water is increased whereby more heat is given oil. by the unit conditioners 88 and this becomes quite advantageous during'morning pick-up cycles. In this manner the building temperature may be rapidly restored to the normal value in the morning following a night shutdown.

Cooling fluid for summer cooling is supplied to the unit conditioners 88 from a mechanical refrigerating apparatus. This refrigerating apparatus may comprise three compressors, one of which is shown at 88. The compressors 88 dis charge into a condenser 84 and the condensed refrigerant passes throughan expansion valve 85 into an evaporator forming a .part of a heat exchanger 88. The evaporated refrigerant is drawn from the heat exchanger 88 by the compressor 83 and recompressed. Each compressor 83 is operated by an electric motor 81.

Cold water is'taken from the heat exchanger 98 through a pipe 88 and passed through a threeway mixing valve- I88 to a pipe I82. The valve I88 is controlled by a proportioning motor I8I similar to the proportioning motors I8 and 88. The cold waterthen passes through a valve I88 to the pipe 18 and thence to the supply header 11 for distribution to the heat exchangers 88 of the unit conditioners 85. Water is retumed from the unit conditioners 88 to the return headleads to the supply header l1 therefore receives coldcooling fluid from the pipe 88 and relatively warm return cooling fluid from the pipe I81, the relative amounts of which are controlled by the three-waymixing valve I88.

The compressor motors 81 are controlled by temperature controllers I88, I88 and H8 responsive to the temperature of the cooling fluid leaving the heat exchanger 88. The arrangement being such that cooling fluid leaving the heat exchanger 88 is maintained at .a substantially.

constant temperature. The manner in which the compressors are controlled is shown speciimixing valve I88 is operated to increase the amount of cold cooling fluid taken fromthe pipe 88 and decrease the amount of "return cooling fluid taken from the pipe I81. Vice versa as the temperature in the pipe I 82 decreases the amount of cooling fluid taken from the pipe 88 is decreased and the amount of return cooling fluid taken from the pipe I81 is'increased. In

this manner cooling fluid at a constant temperature is delivered to the heat exchangers 88 of the unit conditioners 85 in the summer time. I a 1 It is evident that if the relative humidity in the various spaces is relatively high, the moisture in the air will condense on the heat exchangers 88 of the unit conditioners 88 "during the'summer time. This water of condensation is liable to trickle out on the floors and stain or ruin the finish thereof. In order to prevent this conden sation of. moisture onthese heat exchangers in the summer time a dew-point controller 2 is utilized for preventing the operation'ofthe circulating pump 82 when the dew-point temperae ture of the air in the spaces or rooms'decreases to the temperature of the heat exchangers. Although any type of dew-point controller-for accomplishing this result maybe utilized, a parthe heat exchangers 88 of. the various unit conditioners 88 is controlled by a valve Illwhich in turn is operated 'by a'motor H8. The motor H8 is controlled by athermostat I I8 responsive to the temperature of the air in the associated room. A summer-winter change over switch I I8 reverses the controlling action of the room thermostat so that in the summer time when the space temperature increases above a desired value, the valve H8 is opened and in'the winter time when the space temperature decreases below a predetermined value the valve II, is also opened. A switch I I1 is provided for placing the motor under the control of the thermostat H8 or for closing the valve I I8 regardless of the demand for cooling or heating by the space thermostat. The particular manner in which the space thermostat II8 controls the motor II8 to operate the valve I I8 is specifically shown in Figure 2. e

Located in the basement 28 of the building is a master control panel I28. This control panel I28 has control means and indicating means located therein for controlling the-operation of the various dampers and for indicating the static pressures existing throughout the building. The details of construction of this control panel I28 are shown in the lower portion of Figure 8. This invention contemplates theme of static pressure regulators I2I to I28 which may be ot'the type shown and described in application Serial No.

regulators is'shown in the :upper left-hand poritlonof Figure 8. These static pressure regulatorsinclude an inverted-bell the underside of.

which is'connected to a pipe I28 whichextends upwardly to the roof of the building and on the upper extremity of the pipe I28 ismounted a weather vanegenerally designated at I29. 'This weather vane I29 includes a; vane I30 andat all times points an opening I3I into the'wind. The opening I3I connects into the pipe I26 and there fore the'wind' pressure of the outdoor static pressure as. affected. by the .wind transmitted through the pipe I28 to the space underneath the bellsjinto. the pressure regulators. I2I to 126 inclusive. The space above the bellsof each pressure regulator I2I, I22 and I23 is connectedby a pipe I33 into the corridors 2|, I9 and .I8 respectively. Thus the pressure regulators I2I', I22and I23 respond to thedifferential in pressure exist ing .betweri the outdoor static pressure as affected by wind and the static pressure on each board I located inthebasement 255 of the secondthird and fourth floors. The static pressureregulatorlfl has a pipe I34 for causing communication between the portion above the bell ;and the passage 29. whereupon the pressure regulator {I24 responds, to the differential in pres.- surebetween the outdoor :static pressure as afiected by wind and thepressure within the passage 2 9. A pipe I35 connects the spaceabove the bell .of the static pressure regulator I25 :to the duct 5I which delivers conditioned air to the first portion abovethebell in the static pressure regu lator I26 is-connected by a pipe I36 to the space and therefore-this pressure regulator responds may be the usual two position motor having terminals I50, I5I and I52. The arrangement is be supplied to power terminals I55 and I56 on the motor I.I5.from lines wires- I53 and I54. The

- linewires I53 and I54 also connectto terminals I51 and I58 ofa fan switch. When the switch I59 of the fan switchis closed a circuit to the fan motor 61 is completed as isobvious from Figure 2. The switch II1 comprises a terminal I60 and a terminal I6I which are adapted to be engaged by tothe difierencein pressures between the out- 7 door static pressure as afiected by wind and the static pressure within the space II. Allof. the

various pressure regulators and damper motors are connected by suitable conduits to the panel Referring now "to Figure 2,.a more. complete description of the control of the valve II4 which controls the supply of heating ;fluid and cooling fluid to the unit conditioners 7-65 in each room is ,shown. The thermostat. II6, may compriseia chamber I38 containingabellows connected by;a

capillary tube I397 to a bulb 0.. The chamber.

I36, tube I39, and the bulb I contain a volatile fluid so. that upon an increase-in temperature affecting the bulb I40 the bellows in the chamber I I33 is operated to move a plunger I4I upwardly.

The bulb I40 may respondto room temperature directly or may respond to roomv temperature indirectly by being located on the inlet side of the fan 61 in the conditioning unit 65. .Plunger 'I4I operates a lever I42 about a pivot I43. The lever I42 is urged in-onedirectionby a tension spring I44 which may be adjusted by a suitable screw I45. The lever. I42 carries an arm I46 which opa switch arm I62/J When the switch arm I62 engages the terminal I60 the valve H4 is placed under automatic operation and when the switch arm I62 engagesthe terminal I6I a'circ'uit completed across the terminals- I5I' and. I52 of the motor II5 to close the valve H4. The sumrmer-wint er changeover switch II8 comprises winter terminals. I63 and I64and summer termi nals I65 and I66 which are adapted to'beengaged by switch arms I61 and I68.

value, mercury engages the common electrodeand the right electrode of the mercury switch I48 tofcomplete a circuit across the terminals I50 and I5I of the motor ,II5 whereupon the floor and therefore'this static pressure regulator Valve is closed} p n' a ase in tem- I25' responds to the, difference in pressure between perature the mercury bridges the common electrode and'the left electrode of the mercury'switch I48 to complete a circuit'across the terminals I50 and I52 of the motorfII5 whereupon the. valve:

-II4 is'moved to an open position. In this manner the valve H4 is moved to an open position upon a decrease in temperature during the winter time and is moved to 'a'.clo'sed position upon an increase in temperature. Assume now that the switch arms 1 I61 and I68 are movedinto engagement with the summer terminals I 65 and I66. The operation of the motor II5 by the thermostat H6 is therefore reversed, and the valve 4 will be moved to a closed position when the temperature affecting the bulb, I40 decreases 'below' a predetermined value and will be moved to an open position when the temperature affecting the bulb I43 increases above a predetermined value. In this manner the supply cf heating fluid or cooling fluid to the unit conditioners is thermostatically controlled in the summer time as well as in thewinter timelby. the same thermostat to maintain predetermined temperatures within the various spaces.

The manner .in which the compressors of th mechanical refrigerating apparatus are operated is shown in Figure 3. The three compressors are shown at 91, 91A and j91B. The thermostat I08 controls the operation of the compressor 91, thermostat I09 controls. the operation of W the compressors 91A and the thermostat I I0 controls the operation of the compressors 913. Each thermostat may comprise a chamber I10 containing aibellows connected by a capillarytube III to a bulb I12. Therbulb I12 as'pointed out before, is responsive to the temperature of the. cooling fluid leaving the cooler or heat exchanger 96. The bulb I12 contains a volatile fluid and upon an increase in temperature the bellows in the chamber expands to move a plunger I13 upwardly which operates a lever I14 about a pivot I15 against the action of a tension spring I18. The tension of the spring I15 and consequently the temperature setting of the thermostat may beadjusted by a suitable screw I11. The lever I14 operates a mercury s w itch I18, the arrangement being such that when the temperature increases to a predetermined value the switch is moved to a circuit making position.

The thermostat I08 controls a relay or starter.

I19, thermostat I09 controls a relay or starter I80 and the thermostat IIO controls a relay or starter I8I. to comprise a relay coil I82 and switches I83 and I84. Power is supplied to'the relay coils I82 by line wires I88 and I88 and power is supplied to the switches I88 and I84 of the relays slider I88 movesfto the right to decrease thepipe I01. Upon a decrease in temperature the amount of cold cooling fluidcoming from the pipe Each relay or starter is shown I by line wires I81 and I88.

Assume now thatthe thermostat H0 is so adjusted to close its mercury switch when the temperature increases to 40", that the thermostat I09 closes its switch when the temperatureine creases to 42 and that the thermostat I08 closes its switch when the temperature increases to 44. Assume also that thetemperatureincreases to 40 whereupon a circuit-is completedfrom line wire I85 through mercury switch I18 of thermostat H0 and relay coil I82 back t the other line wire I88. The switches I88 and I84 are therefore: closed and the compressor 91B is placed in operation. When the temperatureincreases to 42. the compressor motor 91A is placed into operation in exactly the same manner by the thermostat I09 and when the temperature increases to 44 the thermostat ,I08 brings the thermostat I01 into operation. As

shown in Figure 3 the temperature of the cooling fluid is between 40 and 42' whereupon the compressor motor 813 is operating. while the compressor motors 91.4 and 91 are not operating.

7 Figure 4 shows the manner in .which the threeway mixing valve I00 iscontrolled. Aspointed out above the three-way mixing valve controls the amount of cold cooling fluid and the amount of return cooling fluid delivered to the heat exchangers 88 of the unit conditioners. The thermostat III which respondsto the temperature of the cooling fluid leaving the mixing valve I00 may comprise a chamber I80 containing a bellows connected by a capillary tube I9I to a bulb I92. The bulb I92'contains a volatile fluid and responds to the temperature of the cooling fluid in the pip'e I02 leaving the three-way mixing valve I00. Upon an increase in temperature the volatile fluid expands to move a'plunger I93 upwardly to move a lever I84 about a pivot I95 against the action of a tension spring I96. The amount of tension in the spring I 98 and consequently the temperaturev setting'oi' the thermostat III may be adjusted ,by means of a suitable screw I91. The lever I94 operates a slider I98 with respect to a potentiometer resistance element I99. The slider I98 and the resistance means-of line wires connected to power term nals 203 and 204 of the-motor IOI.- Upon an increasein. temperature the slider I98 moves to the left which proportionately operates the motor IOI to increase the amount of cold cooling fluid received from the pipe 99 and decrease the amount of return cooling fluid received fromthe 98 and increasing the amount oi return cooling fluid coming from the pipe I01. In this-manner the three-way mixing valve I00 is modulated in accordance with changes in temperature tomaintain a substantially constant temperature in the pipe I02. For a more complete description of the operation ofthe motor IOI reference is made to the above referred. to Taylor and Cun-, ningham patents. v "For the control .of the steam supply to the heat exchanger18 reference is made to Figure 5. Since the temperature controller 89-and; the compensator 90- may be exactly the same in construction as the thermostat III of Figure 4 like reference characters have been utilized. The motor 16 of Figure 5 is exactly the same as motor IOI of Figure 4 and therefore the temperature controller 89 is electrically connected to the motor 18 in exactly the same manner as the, temperature controller III is connected to the motorl0| of li'i g ure 4. The temperature controller 89 operates the motor 18 in 'exactlythe same manner as does the temperature'controller III operate the motor IOI,of Figure 4. Upon an a increase of hot water temperatureaii'ecting the bulb I92 the valve I15 is modulated toward a closed position in direct proportionofthe amount I in parallel with the controller 89 and controls the valve 16 in substantially the same manner. Upon an increase in outdoor temperature affecting the bulb I92 the. valve I15 is modulated toward a closed position and upon a decrease in temperature the valve .15 is modulated toward an open position. .Theresistance 208' in series with'the slider I98 of the compensator 90 is provided to desensitize the controlling action of the compensator 90 whereby thetemperature controller 89 performs the main control of the .65 during the winter time is adjusted inaccordance with' outdoor temperatures and the temperature. of the water is maintaihedfsubstan-- tially constant for any given outdoor temperaure.

One type of dew-point, controller II2 Which may control the operation of. the circulating pump 82, to prevent condensation from forming on the heat exchangers 88 of the unit condition-- ers 85 is illustrated in Figure 6. This dew-point controller II2 may comprise a casing 208 into which extends a pipe 209 having a polished surface. Cold water at the same temperature as the cooling water delivered to the heat exchanger 68 of the unit conditioners is circulated through thepipe 209 so that this pipe 209 is maintained at the'same temperature as the heat exchangers 66. The casing 208 is provided with vent openings so that the room air may contact the pipe 209. The casing 2081s providedwith a light source 2I0 and a photo-electric cell: 2. A partition separates the light source 2I0 and the photoelectric cell II I so that light is trans- I hiittedto the photoelectric "cell 2| I only byv re- I 1the dampers.

flectionoil' of the polished surface of the pipe 209; when the dew p olnt temperature of the 'air withinthe s ace 2 is above the tempera?- ture'of the'pipe 2.09 the light source 2l0- affects the' photo-electric cell 2 which' operates through a'suitable amplifier .2l3 to energize a relay coil 2 of a relay 2l5. w Eriergiaation of the relay coil 2I4in this manner closes aswitch 2l3 which causes operation or the circulating pump 92. If," however, the dew-point temperature. of the air; should decrease to thet'emperature of the pipe 209, water vapor will condense on the polished surface of thefpipe 209 and cloud the.

surface" whereupon reflection" of light to the photo-electriccell 21 l is prevented; Relay coil 2l4 therebybecomes deenergized and the switch 2| 6 is opened to stop "operation of tiie circulating'pum'p -82 which stops the supply of cold; cooling fluidtofthe heat exchangers 56. In thi s'inann'er condensation'of moisture on the heat exchangers 55 of the unit conditioners 5 5 is prevented. I" I j Figure'l illustrates the manner in which the motors utilized in this invention may'operate For purposes of illustration the moves upwardly to move the slider .23! toward 7 the right. e

. Motor 243 operates cams .244 to249 inclusive'and.

thought/251 at which'time'the switch 250 opens to'extinguish light 256. "Upon furtherrotation The static pressure regulator l2l operates mo tor 243 of a step controller. The motor 243 may.

be or the type shown and described in the above referred to Cunningham and Taylor patents.

ates an'alarm250. Power-is supplied to the lights 255,251.259 and. 259 and the alarm-269 lay-means of-line wires 26! and 252. Assume that the step controller is" in one extreme" position asshown; switches 259 to'254 are open and switch 255 is closed. Assume now that the proportioningmotor 243-operates to move the cams 245 to 249 in a clockwisedirection. The'switch 250'is first closed to light itsassociated 'light'256. Upon further operation the switch is closed to light theswitch m 'closesand li thali'ght 258 at I the same time the light 251 is extinguished. Up-

motor 45 which "operatesthe damper 33'which controls the supply of conditioned-air to the ear-:-

ridor 2 0s theff ourth floor is utilized. The motor 45 operates a -crankarm flfl provided with a pinj22l? Thepin 22! abuts against a lever 222: carried by thepivot of one of the vanes forming' thedamper 33. The vanes forming the on further'rota'tlon to the other extreme position switches 253and254 close and-switch 255 opens. Closure'ofswitch 253 lights' the light 259 andclosure 'of switch 254 sounds the alarm260. In

' this manner the lights 255, 251, 2 5 8'and 259 indamper, '33 "are connected together by a suitable link 224m The ,arm 22: is urged downwardly by 'a'spring'225 and by aweight'225 to maintain normally the damper 33 infa closed position.

Uponenergization of the motor 45 the crank arrn -22ll'is moved upwardly to overcome the biasing"'action of the ispring 225 and the weight 228 to movei'the'damper 33 toward an open positionf .,When the supplyof electrical e er y to the motorf45 iscut off the spring 225 moves the crank arm downwardly and also moves the damper 33 to ai"closed position. If'th spring 225 should brealg thejweight 225 will' perform this function. Inthisfmanner whenfthe' motor 45 is energized the; damper 33 is opened and when thef'rnotor 45 is deenergized 'the damp'er 33 is closed.

- Referring-now to .theupper left-hand'portion of Figure; 8' thestatic jpres'sureregulator l2| is shown "to comprise a chamber 239 having,'an'in-;

verted bell 23l therein;- I The inverted bell 23] is carried bya rod"232-which is connected to one end of a' tension spring 233. The other end of the tension spring 233 is connected to a suitable adjustable mechanism 234"'whereby the pressure gse tting of the-instrumentmay be adjusted. The

rod 232 operatesj link 235 which is connected I to a bell crankleverf235 The bell crank leve'r 235 carries asliderl23lgadapted to'sli'de across a resistance element 238;, The slider 231 and the resistance' element 233. form a control potentiometer. The slider 2311s connected .to a terminal 239,,the right end of' the resistance element 2331s connected to a terminal 245 and the left "end of -the resistance element 233 is connected to a terminal 24!; Upon an increase in the pressure differential formed by thestatic pressure on'bothside's of the bell 23l,"the bell 23! moves downwardly to move the slider 231 towards the left. Upon ,a decrease in pressure dicate the -position-of the proportioning motor 243 and when the proportioning motor is moved to one extreme position the light 259 .and the alarm 260 indicate'this position.

- are connected to thebusses 261 and 268: The

proportioning mot0r'243'is provided with three.

controlterminals 212,213and 214 which-are con nected respectively'to theterminals 24 I 240' and 239 of thestatic pressureregulator l2l. Assume that the pressure differentialibetween the out 1 door pressure as affected by wind and the pres-' sure in the. corridor 2| is a maximum, then the step controller operated by the motor 243 will be in the position shown in-Figure 8. As the pressurediiferent'ial decreases the lights 256, 251; 253and 259 are progressively lighted in accordance with the amountoi' decrease in this pressure differential. When the light 259 is lighted and the alarm'26ll is sounded-the switch-255 is opened. In thismanner the differential-cr messure Il between the outdoor static pressure as affected by wind and the static'pres'sure on the fourth floor isindicated -by the step controller operated by the motor 243 and when this pressure differential decreases to a given value an alarm is sounded and the switch 255 is opened. It the'proportioning motor 243 should be operated by the static pressure regulator l2 [to an extreme position where the switch255 is opened, thestep controller-may be operated to the other extreme differential afiecting-the bell 23!, the bell 21 I motor 243 and therefore like reference charac ters are utilized. This latter step controller in- I dicates the differential in, pressures existing on the third floor, The static pressure regulator I23 which responds to the differential in pressures; between the outdoor static pressure as affectedby wind and the static pressure on the second floor controls the step controller operated by the c proportioning motor 213 and therefore an indication of the pressures involved onthe second floor is afforded.

Power is supplied to all of the damper ,motors by means of line wires 230 and 2". When the switch 255 of the step controller operated by the proportioning motor 243 is closed a circuit is completed from the line wire 230 through switch 255, terminals 232 on-the damper motors ,45 and -closing of all of the dampers.

vent the fire from being blown through the dampwhereupon all the damper motors would move to a closed position. The fusible links 230 to 233 are utilized for fire preventionpurposes. The fusible links 230 to 234 are located in thepa'ssage, 23 adjacent to the dampers to34 and the fusi--' ble links 234. to' 233 are located in the duct 5| adjacent the dampers 52 to 55. If a fire should.

occur inthe passage 23 or the duct 5| the fusiis ble links near the fire would break and cause deenergization of relay coil 235 and consequenters into the corridors and rooms and also prevent 45 for the fourth floor, terminals 233 of these 1 damper motors 45 and 43 and switch 234 operated by a relay coil 235 back to the other line wire 23 I. When the switch 255 of the step controiler'operated by the pressures onthe fourth floor is closed, power is supplied to the damper motors .45 and 46 and therefore dampers 33 and 34 will be .operated to supply conditioned air to the fourth floor. In a like manner power is supplied to the damper motors 43 and 44 to open the dampers 3| and 32 on the third when the switch 255 of the step controller operated by the proportioning motor 211- is closed in: response to pressures on the third floor, In this manner the dampers 3i and 32 suppiying conditioned air to the third floor are maintained openas long as the pressure differential on the third isabove a desired minimum value. Similarly power is supplied to the damper motor 42 when the switch 255 operated by the proper-- tioning motor 213 is closed in response to pressures on the 1 second floor. Conditioned airis thereupon delivered to the second floor. From the circulation of air through the building to prevent spreading of the fire throughout the building, I V

Referring now to the upper right-hand portion of Figure 8 the static pressure regulator I24 which responds to the differential between the outside static pressure as affected by wind and the static pressure in the passage 23 controls the operation of a proportioning motor 300 of a step controller. Power is supplied to theproportioning motor 300 by a step-downtransformer 30| having a primary 302 and a secondary 303 connected to the power terminals of the proportion ing motor-, The proportioning motor is connect- 7 ed by three wires to the static-pressure regulator I24 so that it is positioned in accordance with changes in the pressure differential; The proportioning 'motor 300 which may be of the type illustrated in the Cunningham andTaylor patents operates cams 304, 305, 30.6 and 301. The

cams 304 to 301 operate switches 303, 303.110 and 3 respectively. The switches 303 to 3 control the supply of power from line wires 3l2 and ,3l3 to relays 3, H5, 3" and 3", respecthe above it is seen that when a desired pressure It is also seen that as the switch 234 controlled by the relay 235 is opened the power supply to.

the damper motors 42, 43, 44, and 43 'will be out oif and all of these dampers will be moved to a closed position. Power is supplied 'to the relay coil 235 by meansof a step-down transformer 231 having a' primary 233 connected across'the line wires 230 and NI and a secondary- 233. The left end of the secondary 233 is connected through a fusible link 230 associated with the motor 42 on the second floor, fusible links 23l and 232 associated with the motors 44 and 43 respectively onthe third floor, fusible links 233 and 234 associated with damper motors 45 and 43 on the fourth floor, fusible links, 235, 236, :23! and 233 associated with damper motors 32, 5 l, and 53 respectively on the first floor and relay coil 235 back to the right side of-the secondary 233.

links are connected in series with relay coil 235 tively. The relay 3 controls the supply of power to the fan motor 33 and to the damper motor 40. The relay 3l5.controls the supply of power'to the fan motor 33A and to the damper motor 40A. Similarly the relays 313 and 3H control the supply of power to fan motors 333 and 33C and'damper motors 40B and 4 0C. 'With i the parts in the position shown the pressure differential is at a maximum'and the proportioning .motor 300 is' in one extreme position.- Upon a decrease in the pressure differential the proportioning motor 300 is operated to [first'close,the switch 303 which operates the fan 33 and energizes the damper motor 40 which opens the damper 33 whereupon a given amount of conditioned air is delivered to the passage 23 for distribution through the second, third and'fourth the fan motor 33A is operated and the damper motor 40A is energized to open its damper 30.

Since all of the above enumerated fusible Upon further decreases in pressure differential the fans 33B and 330 are sequentially broughtin operation and the damper motors 40B and 400 are energized to open their respective dampers. Byv reascnof this construction a substantially constantpressure differential between the outdoor static pressure as affected by wind and the pressure within the passage 23 is maintained.

JIhejstatic pressure regulator I25 operates a proportioning motor 320 which receives its power from-a step-down transformer 32l having a pri- This would premary 32.2'and a'seco'ndary 323 connectedito the I power'terminals of the pr'oportioning motor 320, The p'roportioning' motor 326. operates cams .324,

325.326 and 321 for sequentially'closing switches 323$3 ,330 and 33|.'.These switches control 'relays'w ch inturncontrol thejpla'cing'inom eration oLthe'four fans 56jand'the fourdampers i 53 'ofgthe air conditioning apparatuswhich d'eliversconditioned air to the first floor. Since this method of control of the supply of 'condi tioned air to the first floor is accomplished in the sanie manner-as that for the second,-third and staticf'pressure as affected by wind and-the static pressureintheductfl, 7 I They static pressure regulator I26 {which respon ds to the differential in pressured! the outside static pressure as affected by wind and the I static pressure on'the first-floor controls a pro-* causing this decrease in pressure difierential; Also if any of the-fusible links should break the .1 relay coil 285.would become deenergized to open 1 the switch 284 to break the supply of 'powerto the'dampermotors 59, 60,'6| and 62. Thusif a 'flre should occur in the building the dampersfor thefirst floor would close as well asthe dampers for the remaining floors. 'From the above it is seen that the "dampers controlling the supply of conditioned air to the first floor. are modulated in accordance'with the differential in pressure between outside static pressures as affected by wind and the static pressure onthe first. floor, that the differential of. pressures is indicated by a step controller in the basement and that the. dampers 52, 53, 54' and 55 will closein case the, V

pressure-differential decreases to a predetermined portioning motor 335 which receives it's supply' I r of power from.a step-downtransformer 336 hav ing aLprimary 33'1 and a secondary 333whichis connected to the power terminals of the proper- V tioning'motor'335. This prop'ortioning motor 335 operates sliders 333, 343, 34|,342' "and-1343 with respect to'resistance elements 344,345,346, 34'] and 348. The sliders a'n'dthe resistance elements ing through an outlet duct 362. into the basement; The fans 36| may be operatedby a plurality of motors 363fand the discharge ducts may be provided with aplurality of dampers 364 controlled by damper motors 365., The-motors 363 and the damper motors 365may be conform control potentiometers The slider 333 and resistance element 344 control the operation of the spring return type proportioningmoto'r- 59 which positions the voluine' damper 52 on the first floor. Similarly the slider 340 and the resistanefelement 345 controlthe proportioning connected .by a pipe 361 totheoutside air and the. overside of thebell connected by a pipe 368 to-the basement. Since the pipe 361 is not conmotor 66, the slider 3 and resistance element;

346 controls'the proportioning motor 6| andthe' slider 342 and the resistance element 341 con-i trol theproportioning motor 62; Proportioning motors'53,60,-6|and 52 operate the dampers 52, 53, 54 and 55 which control the supply of conditioned air to the first floorpf the building.

These proportioning motors as pointed outabove are of the spring return type as disclosed in the above referred to ,Gille patent. As the pressure differential increases the motor 335 is modulated 1 to move the sliders which in turn modulate the motors; 66, 6| and 62 so that the dampers 52,

53, 54 and 55 aremodulated' in accordance withstantially constant pressuredifferential between outdoor static pressures as affected by wind and the static pressure on-the firstfloorq 1 r The slider 343 and theresistanceelement 348 form acontrol potentiometer for the proportionmg motor :213 of the step controller located in thepanel I25. This step controller performs an indicating function in exactly-the same manner I l as the other step controllers contained in the.

the differential in pressure to maintain a sub-1 nected' to a weather vane, the static pressure regulator 366 will operate in response to the differential of outside static pressures and base-. ment pressures. This 'mode of operation isall, right 'for the basement' since wind pressures would have substantially no effect in the basement. f The. basement maybe heatedor cooledby means of unit conditioners 310suitablyconnected to,the supply-and returnheaders 11 and From the above it is seen that I have provided an air conditioning control system for abuilding wherein the building is heated or cooled by means of unit conditioners, wherein these unit condi: tioners are controlled by room thermostats pro- I vided with summer-winter changeoverswitches, wherein heating fluid, the temperature of which (if n is varied in accordance with outdoor temperatures, is supplied to the unit conditioners in the winter time and wherein a cooling fluid at a constant temperature'is supplied to the unit c'on-. ditioners in the summer time. Provision is made for-varying the head pressure on the cooling and heating system so that the rate at which.

thebuilding temperature maybe restored to the desired normal value following a night shut-down may be speeded up. Conditioned 'airat afdesired. temperature. value and moisture content value is delivered to the building mainly for the purpose of ventilating the building and controlcoil235 back-to the other linewire28l. Therefore, ifthe pressure diflerential of the first floor should decrease to a'pr'edetermined low value the switch 255 would open and-the power. supplied to the damper motors 53, 65, 6| and 62 would .be'

brokenwhereupon the dampers 52, 53, 54and 55 would move toja closed position. This might ocour if the'windows' on the first floor were opened ling the relative humidity in the building. The supply ofthis air to the building is so controlled that a substantially constant predetermined pres-; I.

sure differential is maintained. between theoutside static pressure as afiected by wind and the inside static pressure so that a positive pressure is at all times maintained within the building to through crevices around the windows. Provision is further made for controlling the static pressures on the main or first floor of the building along with means for indicating the static pres-j sures. l V

In case the pressure differential of the portion of the buildingshould decrease to a predetermined low value the dampers controlling the supply of air to that portion of the building will close. The decrease in pressure differential would most likely be caused by the opening of windows and therefore the closing 'of these thereby decrease the probability of the fire spreading throughout the building.

Although for purposes of illustration I have disclosed one form of my invention, other forms thereof may become obvious to those skilled in the art upon reference to this specification and therefore this'lnvention is to l be limited only by the scope of the appended claims and prior art. 1

I claim as my invention:

1. In an air conditioning system for an enclosure, the combination of, means for supplying conditioned air under pressure to the enclosure, a pitot tube located outside of the enclosure and adapted to be pointed into the wind regardless of the direction of the wind, a vane for pointing the pitot tube into the wind, a differential pressure responsive controller having a pressure connection to the pitot tube and a pressure connection to the inside of the enclosure so 3. In an air conditioning system for an enclosure, 'thecombination of, means for supplying conditioned air underpressure to theenclosure, a differential pressure responsivecontroller having a pressure connection outside of the enclosure and a pressure connection inside ofthe enclosureso as to respond to the difference in air pressure inside of the enclosure-and'the air pre sure outside of the enclosure, '9. power failure type variably positionable mechanism for regulating the supply of conditioned air to'the" enclosure to interrupt the supply of conditionedair to the enclosure when the supply of power to the mechanism is interrupted, to supply conditionedair to theenclosure when power is supplied to the mechanism and to regulate variably the supply of conditioned air to the enclosure while power is supplied to the mechanism,'means controlled by the differential pressure responsive controller for variably controlling the mechanism to regulate variably the supply of conditioned air to the enclosure to maintain an enclosure air pressure which is greater by a substantially conas to respond to the diiference in air pressure in the enclosure and'the air pressure outside or the enclosure as affected by wind, and means controlled by the differential pressure responsive controller for controlling the conditioned air supplying means to maintain an enclosure air pressure which is greater by a substantially constant amount than the outside air pressure as affected by wind whereby infiltration of outside air is prevented regardless or wind velocity,

2. In an air conditioning system for an enclosure, the combination 01, means for supplying conditioned air under pressure to the enclosure, a pitot tube located outside of the enclosure and adapted to be pointed into the wind regardless of the direction of the wind, a vane for pointing the pitot tube into the wind, a differential pressure responsive controller having a pressure connection to the pitot tube and a pressure connection to the inside of the nclosure so as to respond to the diflerence in air'pressure in the enclosure and the air pressure outside of the enclosure as affected by wind,,means controlled by the differential pressure responsive controller for controlling the conditioned air supplying means to maintain an enclosure air pressure which is greater by a substantially constant amount than the outside air pressure as affected by wind whereby infiltration of outside air is prevented regardless of wind velocity, and means controlled by-the diflerential pressure responsive controller for also controlling the conditioned air supplying means to prevent the supply of conditioned air to the enclosure if the difierential in pressure between the enclosure air pressure and the outside air pressure decreases to a predetermined value.

stant amount than the outside air pressure whereby, infiltration of outside air is prevented, and means controlled by the differential pres-/ sure responsive controller for interrupting the supplytof power to the mechanism to interrupt the supply of conditioned air, to the enclosure if the differential in pressure between the enclosure air pressure and the outside air pressure decreases to a predetermined value.- v

4. In an airconditioning system, the combination of a conduit for supplying outside air to a building for air conditioning purposes, a plurality of fans for forcing outside air into the conduit to build up a static pressure in the conduit, means responsive to the static pressure in the conduit for placing the fans in operation in sequence as the static pressure in the conduit decreases to maintain a substantially constant static pressure in the conduit, a damper associated with each fan and operative when closed to prevent communication between the outside atmosphere and the conduit whereby the pressure in the conduit is prevented from venting to atmosphere, and means for opening each damper when its associated fan is placed in operation.

5. In an air conditioning system for an enclosure, the combination of, means for supplying I conditioned air under pressure to the enclosure, a power failure type variably positionable mechanism for regulating the supply of conditioned air to the enclosure to interrupt the supply of conditioned air to the enclosure when the supply of power to the mechanism is interrupted, to supply conditioned air to the enclosure when power is supplied to the mechanism, and to regulate variably the supplyof conditioned air to the enclosure while power is supplied to the mechanism, a difierential pressure responsive controller having a pressure connection outside of the enclosure and a pressure connection inside of the enclosure so as to respond to the difference in air pressure inside of the enclosure and the air pressure outside of the enclosure, means controlled by the differential pressure responsive controller for variably controlling the mechanism to regulate variably the supply of conditioned air to the enclosure to maintain an enclosure pressure which is greater by a substantially constant amount than the outside air pressure whereby infiltration of outside air is prevented, and means operative upon the occurrence of fire in the enclosure for interrupting the supply of power to V d I I the mechanism interrupt the uppl of conditioned air to the enclosure.

6, In $111311 conditioningv system for an .en-" closure,- the. combination of, means for supplying V V conditioned airu der pressure to the enclosure,

a power failure type variably positionable mechv a ism fo resu at z hesupply of conditioned ,air to the enclosure to; interrupt the, supply or conditionedair to the enclosure when the supply of power to the mechanism is interrupted, to sup ply conditioned air to the enclosure when: power 7 is supplied to the mechanism andQto regulate variably .-the supply of condition'edair to the enclosure while power is supplied to the mechanism, a diiIerential pressure responsive controller having a pressure connection'outside of the enclo-,

sure and a pressureconnection inside of the enclosure'so as to respond to the difference in'air pressure inside of the enclosure and the air pressure outsideot the enclosure, means controlled by the difierential pressure responsive controller for variably controlling the mechanism to regulate variably the supply of conditioned air to the enclosure to maintain an enclosure vair pressure which is greater by a substantially constant amount than the outside air pressure whereby infiltration or outside air is prevented, means I ential in'pressure between the'enclosure air pres-x sure and the outside air pressure decreases to aoperative upon the occurrence of fire in the en-j closure for interrupting V the supply} of power to 5 the mechanism to interrupt the supply of con ditioned air to the enclosure, and means ton; trolled by the diiferential pressure responsive controller for also interrupting the supply for power to the mechanism to interrupt the supply of conditioned air tothe' enclosure it the'difierpredetermined value.

7.'In an ,air. conditioning system for an enclosure, the combination of; means for supplying conditioned' air under 'pressure'to the enclosure,-

mechanism for regulating the supply Of'conditioned air to the enclosure, a differential pressure responsive controller responsive to the difference in air pressure inside of the enclosure andth'e- 

